Hdr Compander Effect; To Use The Hdr Compander Effect - Adobe AFTER EFFECTS 7.0 Manual

Original (left); the Wave Warp effect is constrained by the dimensions of the layer (center); Grow Bounds fixes this problem (right).

HDR Compander effect

The HDR Compander (compressor/expander) effect gives you a way to work with tools that don't support HDR—
such as 8-bpc and 16-bpc effects—without the sacrificing the high dynamic range of your footage.
The HDR Compander effect works by first compressing the highlight values in the HDR image so that they fall
within the range of an 8-bpc or 16-bpc file, and then expanding the values back to the 32-bpc range.
Apply the HDR Compander effect to your footage once before working with low-dynamic-range tools and effects.
Then, when you're finished, use the HDR Compander effect to expand the dynamic range back to 32-bpc.
Because the first application of the HDR Compander effect compresses the range of values through sampling, some
accuracy is lost. Only use the HDR Compander effect if you are willing to make the tradeoff of some accuracy in
values for the sake of high dynamic range.
See also
"High dynamic range footage (Pro only)" on page 62

To use the HDR Compander effect

Select a layer in a 32-bpc project, and choose Effect > Utility > HDR Compander.
1
In the Effect Controls panel, select Compress Range for the Mode property.
2
Set Gain and Gamma. Gain specifies the maximum value to be represented in the compressed range; Gamma
3
affects the distribution of values in the range, allowing more precision in specific areas of the range.
4 Apply whatever low-dynamic-range effects you choose to the layer.
Apply another instance of the HDR Compander effect to the layer. Make sure that the second instance of HDR
5
Compander is ordered after (below) any 8-bpc or 16-bpc effects you have applied.
6 In the Effect Controls panel, select Expand Range for the Mode property for the second instance of the HDR
Compander effect.
Set Gain and Gamma to the same values as set in the first instance of the HDR Compander effect.
7
A more convenient way to use the HDR Compander effect is to apply the Compress-Expand Dynamic Range
animation preset. This animation preset consists of an expression and two instances of the HDR Compander effect:
The first instance has Compress Range selected, and the second has Expand Range selected. The expression automati-
cally sets the Gain and Gamma for the second instance to be the same as that which you set for the first instance. Insert
whatever low-dynamic-range effects you choose between these two instances of the HDR Compander effect.
See also
"High dynamic range footage (Pro only)" on page 62
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